Word Processors: Stupid and Inefficient: This essay is years old, but it high-lights some points about WYSIWYG editing that are still very true today.
The author is distracted from the proper business of composing text, in favor of making typographical choices in relation to which she may have no expertise (“fiddling with fonts and margins” when she should be concentrating on content). […]
The user of a word processor is under a strong temptation to lose sight of the logical structure of the text and to conflate this with superficial typographical elements.
This is still true today, and it’s why I don’t care for WYSIWYG that much — it simply distracts people from writing the text they’re supposed to be writing.
If you have to do WYSIWYG in terms of Web content, there are good editors out there that let you neuter the interface so much that all the user can do is pick from some styles that (1) impart structure to the document, and (2) centralize formatting.
(I have had great luck with eWebEditPro for this — great CSS support in that tool)